Screen issues- flickering Line and inverted looking colours

Flickering lines usually indicate a hardware issue with the Display Assembly itself which will require repair.

I don't see any lines in the picture, but I can see that things don't look right in the picture, but I'm also not sure what they are supposed to look like either.

Try connecting an external display and enable mirroring. Does the external display also show the same issue or is it only on the laptop's built-in display? If it only shows on the laptop's built-in display, then you have confirmed a hardware issue with the laptop's built-in Display. If both displays show the problem, then maybe it is a software or configuration issue, or possibly a hardware issue with the Logic Board. If you don't have an external display, then take a screenshot of the affected area and view the screenshot with another device. If the screenshot looks good, then the laptop's built-in Display has a hardware issue.

Have Apple or an Apple Authorized Service Provider examine the computer to provide you with a repair estimate.

No, it is unlikely although it never hurts to try them if you want and you have an Intel Mac. The problem is only affecting the internal display circuitry so the main part of the Logic Board is fine. Most likely the built-in display is faulty, although there may be an internal cable or a slim chance a portion of the Logic Board is bad.